Screw-cutting die



(No, Model.)

ILKIN.

SCREW CUTTING DIE. No. 393,288. Patented Nov. 20,1888.

UNITED STATES PATENT OFFICE.

THEODORE S. WILKIN, OF MILWAUKEE, WISCONSIN.

SCREW-CUTTING DIE.

SPECIFICATION forming part of Letters Patent No. 393,283, dated November 20, 1888.

(No model.)

To ttZZ whom it may concern.-

Be it known that I, THEODORE S. WILKIN, of Milwaukee, in the county of Milwaukee, and in the State of Wisconsin, have invented certain new and useful Improvements in Tools for Cutting Screw-Threads; and I do hereby declare that the following is a full, clear, and exact description thereof. 4

My invention relates to tools for cutting screw-threads; and it consists in certain peculiarities of construction, to be hereinafter described with reference to the accompanying drawings, and subsequently claimed.

In the drawings, Figure 1 represents a horizontal section ofa screw-cutting die constructed according to my invention, the section being taken on line 1 1, Fig. 2; Fig. 2, asection taken on line 2 2, Fig. 1, and Fig. 3 a plan view of another form of die.

Referring by letter to the drawings, A represents a screw-cutting die, that may be either split, as shown in Fig. 1, or made in two sections, as shown in Fig. 3, either form of die being well known in the art to which my invention relates. In either form of die the threaded portions a 1) thereof have their cutting-edges alternately in opposite directions, and thus when the ones (6 are cutting, the ones I) will be idle, although following those first named; but when the (lie is being run off the screw the cutting-edges of the threaded portions 1) come into play to trim up any irregularities of the thread with which they may come in contact, thereby giving a clean, true finish to said thread throughout its entire length. By the above description it will be seen that all thecuttingedges in one threaded portion of the die face in one direction and all the cutting-edges in each adjacent threaded portion face in an opposite direction; or, in other words, I may take an ordinary die and bevel the threaded portions thereof alternately in opposite directions, thereby presenting the cutting-edges in the same arrangement.

While I have shown a screw-cutting die and described my invention in connection therewith, it is obvious that a screw-cutting tap may be constructed in precisely the same manner and for a like purpose.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A screw-cutting tool having the usual longitudinal rows of thread-cutters, but with the cutting-edges in one or more of the rows pointing in an opposite direction to those of the other row or rows.

2. A screw-cutting tool having the usual longitudinal rows of thread-cutters alternately beveled in opposite directions.

In testimony that I claim the foregoing I hereunto set my hand, at Milwaukee, in the county of Milwaukee and State of Wisconsin, in the presence of two witnesses.

THEODORE S. IVILKIN.

\Vitnesses:

F. A. OLIVER, N. E. OLIPHANT. 

